<!DOCTYPE html><!--鼠标悬停-->
<html>
<head>
    <style>
        a:hover{
            background-color: yellow;
        }
    </style>
</head>

<body>
<a href="http://www.w3school.com.cn">W3Sschool</a>
<a href="http://www.google.com">Google</a>
<a href="http://www.wikipedia.org">Wikipedia</a>
</body>
</html>